1. Field of the Invention
The present invention relates to automatic accompaniment apparatuses which perform automatic accompaniments based on chord data which designate chords to be generated.
2. Background Art
Conventionally, automatic accompaniment apparatuses are known which are called as chord sequencers. In these chord sequencers, a series of chord data, each one of which designates a chord to be generated, are stored in accordance with the progress of a musical piece. When performing the chord accompaniment, the chord data are sequentially read out and the chord accompaniment is automatically performed based on the read out chord data.
In the automatic accompaniment, fundamental patterns, each one of which contains a series of notes, are defined beforehand and the notes of the fundamental patterns are converted into the other notes which are in harmony with the chord designated by the read out chord data. There are chord backing patterns (chord performance patterns) and bass patterns (bass performance patterns) as the fundamental patterns.
In the chord performance, the configuration of a chord is generally determined based on the root and the type. Therefore, the root data and the type data are used for designating the root and the type of the chord to be generated. There are special cases in which a chord containing a special bass tone is to be generated. The chord having such a special configuration is called as on-bass chord. When the on-bass chord is to be generated, the on-bass data is used together with the root data and the type data to designate the generation of the on-bass chord and to designate the special bass tone which is to be included in the on-bass chord.
In the chord accompaniment, the root and the type of the chord is designated by the chord data and a fundamental pattern corresponding to the designated chord type is regenerated. Some notes of the fundamental pattern thus regenerated are then converted into the other notes so that the configuration of the notes of the fundamental pattern conform with the designated type. The notes thus converted are then shifted upward or downward by a pitch shift value corresponding to the designated root.
In the bass performance, the bass tones are generated based on the general bass patterns when no on-bass data is given. In contrast, when on-bass data are designated to generate the on-bass chord, the bass tones are generated based on special bass patterns which are defined beforehand for only the on-bass chords.
The fundamental patterns define the configurations of the notes of the chords for a few chord types. The fundamental patterns are not prepared for the other chord types such as measure-sevens (Maj7), sevens (7) and minor sevens (m7). When generating a chord, the notes defined by the fundamental pattern corresponding to the designated chord type are converted to the other notes having a configuration which are in harmony with the designated chord. The note conversion is carried out based on a note conversion table.
The other type of automatic accompaniment apparatus is known which is capable of programming desired fundamental patterns. The user can perform a desired accompaniment having rich variations by using the apparatus (reference: Japanese Patent Application Laid-Open No. Sho 61-292690). In this type of automatic accompaniment apparatus, some operations are carried out in order to overcome a musical disadvantage.
For example of such a disadvantage, there is a case in which the user makes a fundamental pattern based the previous prepared fundamental pattern for the chord Cmaj7 and the user designates the same chord Cmaj7 as the chord to be generated. In this case, the notes of the fundamental pattern for Cmaj7 should be used with no note conversion. But, if the pattern made by the user contain the note F, the chord makes a musical disadvantage because such a tone is not defined in musical scale. The note conversion table is made so as to overcome such a musical disadvantage. When a chord is designated and the fundamental pattern corresponding to the designated chord makes a musical disadvantage, the notes of the fundamental pattern are converted based on the note conversion table even if the designated chord is identical to the chord corresponding to the fundamental pattern. In the above case, the tone F included in the fundamental pattern is converted to the other note based on the note conversion table.
In this manner, the notes of the fundamental pattern are automatically converted to the other notes based on the note conversion table so as to make no problem even if the automatic accompaniment apparatus is used by the user who does not specifically understand the configuration of the apparatus.
However, there are cases in which the users who have a much talent in the musical art require to generate a special chord containing a note which is not defined in musical scale in order to obtain a characteristic sound. In the conventional apparatus, however, when the fundamental pattern contains a note which is not defined in musical scale, such a note is automatically converted to the other note even if the user does not wish such a conversion. Thus, the conventional apparatuses do not satisfy such a requirement of the user.
Furthermore, the conventional apparatus has an another problem with respect to the designation of the on-bass chord. The on-bass chord is basically designated in order to generate one of the on-bass chords which are defined. However, there are cases in which the on-bass chord is designated by the user in order to generate an agent chord. More specifically, in this case, the user designates the on-bass chord having a chord type in order to generate the other chord, the chord type of which is different from the chord type of the on-bass chord. For example, the on-bass chord Dm7/G (Dm7 on G: "/" means "on") is used in the key C. But, the Dm7/G is usually used as the agent chord of G7sus4. The reason is as follows:
In the on-bass chord Dm7/G, the chord Dm7 consists of the element tones re, fa, ra and do, and the element tones are to be on the bass tone so. Therefore, the element tones of the on-bass chord Dm/G7 G are as so, re, fa, ra and do. On the other hand, the chord G7sus4 is made by modifying the element tones of the chord G7. More specifically, the chord G7 consists of the element tones so, si, re and fa. In these element tones, the element tone si is replaced by the suspended fourth tone, i.e., the tone do to form the chord G7sus4. Therefore, the element tones of the chord G7sus4 are defined as so, do, re and fa. Thus, if the ornament ra is added to the chord G7sus4, the added result equals the element tones of the on-bass chord Dm7/G. The on-bass chord Dm7/G contains the tone ra which is act as the ornament in the key C. But, when considering the musical characteristics of the chords, the on-bass chord Dm7/G is a chord close to the chord G7sus4. And when considering the role of the chords in the chord progression, the role of the chord Dm7/G is same as the role of the chord G7sus4. Therefore, the on-bass chord Dm7/G is used for designating the agent chord of the chord G7sus4 which is more decorative than the chord G7sus4.
In the conventional apparatus, however, the on-bass chord Dm7/G is subjected to the note conversion even if the user designates the on-bass chord as the agent chord of the chord G7sus4. Therefore, the conversion may make the chord which is not in harmony with the other chords in the musical piece of the key G. The same problem may be established with respect to the other on-bass chords which arc used for designating the agent chords. For example, the on-bass chords F/G and Dm7/F are respectively used for designating the agent chords of the chords G7sus4 and F6.